Mammillothalamic tract

The mammillothalamic tract (MMT) (also mammillary fasciculus, mammillothalamic fasciculus, thalamomammillary fasciculus, bundle of Vicq d'Azyr) is an efferent pathway of the mammillary bodies which project to the anterior nuclei of the thalamus. The mammillothalamic tract is part of the Papez circuit (involved in spatial memory), starting and finishing in the hippocampus. The fibers of the MMT are heavily myelinated.

It arises from the medial and lateral nuclei of the mammillary bodies, and from fibers that are directly continued from the fornix of the hippocampus. It connects the mammillary bodies to the dorsal tegmental nuclei, the ventral tegmental nuclei, and the anterior thalamic nuclei.